Products containing psyllium seed husk are widely used for normalizing bowel function and inducing laxation. It has also been shown that psyllium seed husk is effective for reducing human serum cholesterol levels and in controlling blood glucose levels in diabetics. These benefits are typically achieved by ingestion of psyllium seed husk, which is obtained from the seed coat from plants of the genus Plantago. To render a laxative effect, a typical dose of psyllium seed husk in humans is from about 2.5 grams to about 20 grams, taken from about 1 to about 3 times per day. In order to administer such a large amount of psyllium seed husk, the husk is often milled or ground and subsequently dispersed in water or an aqueous beverage for consumption by the user (for example, METAMUCIL®, sold by The Procter & Gamble Company). In addition to milling, typically, sanitization of the psyllium seed husk is performed prior to any further processing, in order to reduce microbial contamination of the psyllium seed husk. This sanitation step can be costly and difficult to perform.
Psyllium seed husk contains natural mucilage, forming a gelatinous mass on contact with water. As a result, milled psyllium seed husk, with its increased surface area, exhibits very poor disperability and mixability in water as the particles can tend to agglomerate. Hydration takes place over the surface of the agglomerated aggregates to form gel-coated lumps, the interiors of which are still substantially dry. These lumps are extremely difficult to disperse. Various methods have been employed to improve the dispersability of milled psyllium husk in an aqueous medium. For example, U.S. Pat. No. 5,425,945 discloses a drink mix composition comprising agglomerated psyllium seed husk with an edible acid uniformly dispersed throughout the agglomerating coating to obtain improved mixability and dispersability.
However, once dispersed in an aqueous solution, the agglomerated psyllium husk quickly hydrates and gels with an accompanying increase in the viscosity of the drink solution. Again, various methods have been employed to reduce this gelation rate and provide an aesthetically pleasing product. U.S. Pat. No. 5,356,618 teaches that the addition of calcium citrate malate to a composition comprising milled psyllium seed husk results in a reduced gelation rate of the husk when mixed with an aqueous solution. However, despite these improvements, the consumer typically drinks the liquid in a relatively short period of time (less than about two minutes) in order to avoid having to drink an aesthetically unpleasant, high viscosity liquid.
Sanitized, milled psyllium seed husk has been incorporated in baked products, such as cookies, crackers and similar food items to render solid dosage forms. However, the rapid gelation of the psyllium seed husk can be noticeable in these preparations as well. Baked products containing such psyllium seed husk have a tendency to begin to gel in the mouth during consumption, resulting in an unpleasant mouthfeel and poor aesthetics. It is generally necessary to consume such baked products with significant amounts of water or aqueous liquid for ease of swallowing. In addition, such solid psyllium seed husk preparations must be large in size or, alternatively, multiple preparations must be consumed in order to deliver an effective amount of psyllium seed husk. Therefore, a psyllium containing composition that is convenient, easily administered and has improved aesthetics mouthfeel is still needed.
Other forms of products containing psyllium include swallowable tablets with acceptable dissolution properties, thus avoiding problems of poor mouthfeel. U.S. Pat. No. 4,999,200 teaches a swallowable tablet comprising psyllium, a binder, a wetting agent and a disintegrating agent. Unfortunately, swallowable psyllium tablets, while convenient, often have poor dissolution properties. Like the powdered drink mix, once introduced into an aqueous environment hydration takes place over the surface of the pill, creating a gel coating, while the interiors of the pill remain substantially dry. For swallowable pills this can lead to incomplete dissolution in the gastrointestinal tract.
Methods of fractionating psyllium seed husk into various polysaccharide fractions are known. Certain of the fractions of psyllium seed husk deliver the same therapeutic benefits as psyllium seed husk. For example, U.S. Pat. No. 6,287,609 teaches a multiple extraction process for obtaining three distinct fractions from psyllium husk, including an alkali soluble/acid gel-forming fraction, an alkali insoluble fraction, and an acid soluble fraction. The alkali soluble/acid gel-forming fraction has a slower rate of gelation than non-fractionated psyllium seed husk. However, appropriate formulation of such fractions in a consumer-acceptable product has still presented challenges.
After significant work toward consumer-acceptable products that contain certain fractions of psyllium seed husk, the present inventors have discovered that compositions comprising particles having a defined particle size, or agglomerates having a defined particle size provide excellent properties, particularly in compositions which are intended for dilution in an aqueous liquid prior to consumption. In particular, it has been surprisingly discovered that compositions containing a defined ratio of xylose and arabinose which have a defined particle size, optionally as an agglomerate in combination with a binder or edible acid, provide excellent mouthfeel when dispersed in an aqueous liquid, excellent dispersion in such aqueous liquid, and decreased sedimentation over time in such aqueous liquid as compared to psyllium seed husk. These and other embodiments and benefits of the present invention are defined herein below.